Plant in spring in a sunny position.
Water the plant thoroughly before planting. Dig a hole 1-1/2 times wider and a little deeper than the root ball. Then water the hole and allow it to drain. Holding the stems between your fingers, tip the plant out of its pot.
Mix the removed soil with some well-rotted compost, and add some more compost to the bottom of the planting hole. If the roots are coiled around the sides of the pot, tease them out carefully.
Place the plant in the hole with its crown at the correct depth, which is usually the same as it was in its pot. Gradually backfill around the plant with the mix of soil and compost, firming gently as you go.